The effect of a polyvinyl alcohol and dextrane on the properties of thermosensitive hydrophilic gels containing lactic acid complexed with chitosan

Gels containing lactic acid complexed with chitosan at a stoichiometric ratio 1:1 and 2:1 and 5 - 25% content of polyoxyethylene glycol 200 reveal pH from 2.5 to 4.6. The addition of 20 – 25% poloxamer 407 increases the pH to 4.55 to 5.30 for 1:1 gels and 4.00 to 4.85 for 2:1 gels. The addition of 0.5% polyvinyl alcohol decreases the pH of the investigated gels to 4.00 to 4.55 for 1:1 gels and 3.85 to 4.40 for 2:1 gels. The addition of 1.0% dextrane decreases the pH of investigated gels to 4.40 to 4.90 (1:1) and 4.00 to 4.48 (2:1). Rheological investigations revealed an increase in the dynamic viscosity of preparations containing poloxamer 407 with the addition of polyvinyl alcohol or dextrane in comparison to the reference gels. Results obtained in the experimental studies proved that it is possible to produce a preparation with optimal pharmaceutical and application properties.